1. Technical Field
This invention relates to a method and apparatus for the separation of dry material into distinct phases, and more particularly for the separation of fibrous bark from core material of chopped or crushed stalks of a crop such as Kenaf.
2. Background Art
The Kenaf plant is composed of stalks having a fibrous bark and core. The former possesses long fibres capable of producing a high quality paper pulp, while the latter is of lesser quality short fibre composition. In some areas of the world the process of recovering the bark fibre comprises cutting and bundling the stalks, which are then dried in the field and then petted with the bark fibre being scutched from the central woody stem. This is a time-consuming task and the bark fibre that is obtained is not optimum for paper pulping.
Proposals have been made for machine processing of the harvested stalks and this has entailed firstly crushing, grinding or chopping the stalks, and subsequently separating the bulk material into separate phases. A modified form of sugar cane crushing mill has been used for the first stage of processing, while in another instance a forage harvester has been used to gather the crop for baling in a finely chopped condition. However, it has not been possible to achieve high quality grading with conventional separation apparatus.